Impulsive fearless 4 year old

My son has always (since he was a baby) been physically adventurous. When he was 10 months old I had to rearrange or remove furniture for fear of him climbing up it. He absolutely loves going to the park but I am a nervous wreck. He is climbing, jumping, running (all the usual things) but completely oblivious or so it seems to physical injury. He has had falls and cuts but just bounces back. Recently I took him to the park and he ran from one apparatus to another in such haste and excitement that he ran between a man pushing a toddler on a high swing and the swing. It was pure chance the swing didn't hit him. I went absolutely ballistic and was completely shaken. Prior to going to the park I talk to my son about what he can and cannot do but to be honest it doesn't have much affect. Children of a similar age seem to be on all the roundabouts, monkey bars etc but take things more calmly. Has anyone had similar issues and what did you do? I appreciate his enthusiasm and sense of adventure but do not want him to have a nasty accident. Similarly when we catch a bus and he is on his scooter I have to constantly hold onto the scooter and remind him to stop, look where he is going etc. He scooters along sometimes completely unaware of what is in front of him until he is practically touching it. I have had his eyesight checked and there is no problem.

This all sounds pretty normal...I have a just turned 6 year old daughter and she's the same. She's up on top of anything that can be climbed and if there's nothing to climb then she's inventing some dangerous game like last night...she got into a sleeping bag...a silky one...and used it like a sledge down the stairs.

The swing incident is a fairly standard experience for all parents of children under about 5 or 6...they all do one of those silly rushes at some point...show him with a model swing or an empty swing...that's what I did. I put a bear on the swing and pushed it and then talked about the pendulum effect...and showed her how heavy it is when it's coming down...she hasn't done it since....but impulsive and energetic kids just have to be watched that little bit more than others.

The scooter issue I would get a handle on though...by not letting him ride it on paths near roads or pedestrians.....we keep ours for the park basically as DD wills just go too fast and on a scooter they're always ahead of you...4 is too young for that.